Let me reach down into the bottom of the Port-O-Pot to retrieve a Brady Bunch hat of Loony Lefty "Logic".... Hat on and here we go...
Why you silly little subject..I mean citizen. It is bad because 500 dead victims of both their complacency and our agenda are VASTLY morally superior to some cowboy, vigilante, Dirty Harry wannabe standing over the body of the poor disadvantaged victim he just murdered with his cop-killer, exploding hollow-point loaded Saturday Night Special Investigation Section high-capacity assault weapon. The so-called "bad guy" (as you so heartlessly mischaracterize this poor, underprivileged soul) in situation 1, is as much, or even more of a victim of "gun-culture" than the 500 convenient statistics...oops I mean 'people' that are shot by the gun. He wouldn't have done it if that gun hadn't been there to attach itself to his hand and force him to "act out" by pulling his finger backwards...500 times.
In situation 2 the murder victim (you slander him by calling him a "bad-guy" just because he allegedly shoots 3 stat...er..people) after only killing about 200 or so...was very likely going to enroll in med school, build an orphanage, or provide the endowment to build a counselling center to help Gay, Lesbian, Bi-sexual, and Transgendered homeless, physically challenged animals to overcome centuries of oppression by the white male patriarchial Bourgeoisie, and to teach the carnivorous ones the virtue of a vegan lifestyle. But of course thanks to Mr. 'John Wayne 2.0', this poor soul will never get to do this thanks to this inbred idiot with a hero complex, his weapon of war, and his license to kill.
Situation 2 is also VERY BAAA-AAA-aaa-aaadd

because is implies that an individual actually has some sort of "right" to defend their life against those who would take it away. This is of course completely preposterous because any properly educated slave..I mean person knows that our lives belong to, and are protected by the kind benevolence of our government, led by those of us that are progressive, liberal-minded people of correct politics; people who have read some philosophy books and thus know how the real world does, or should, work. The State exists to provide everything the masses need, so any displays of individual action and thought are unacceptable. That is why only the State should have guns...individual ownership could possibly make it difficult to taxate, re-locate, concentrate, re-educate, or exterminate those who are so foolish as to not appreciate the wonderful government that is provided by those of us who selfishly...I mean selflessly work to control..oops...lead the people.